I started some maintenance work today. I'm changing the fluid in the front diff, rear diff, and transfer case. After driving it a few miles to warm up the front diff and transfer case fluid I popped the front diff cover off. This is what I saw:





So my question is: is normal for the oil to be this foamy? I understand I just drove it and the gears stirred it up, but I didn't expect it to look like the gears just took a bubble bath...either way it will have new fluid in it tomorrow after the rtv dries overnight.

Here's some more pics of the fun I had in the 15 degree weather this evening:





All of the teeth looked great. No gouges, deep scratches, or uneven wearing.



This is when I was prepping the surface before placing the cover back on.



This was one of my xmas presents this year. It's a set of thread chasers, not to be confused with taps and dies. These are not meant to cut threads. There are used to clean out any dirt or grime in the bolt holes and the bolts themselves. Everyone should have a set if they don't already. I can't wait to use them on everything.



This is after I got the cover back on. While I had it off, I sanded the outside and put a coat of paint on it. Figured it would act as a little extra rust protection and gives it a better appearance overall. Unfortunately I didn't get a picture before I painted. It wasn't that bad to begin with though. Once Autozone gets another bottle of fluid in stock for the rear diff (I bought the last three they had and I need one more) i'll post a few before and after pictures of the rear diff.

For those who keep putting it off (like I kept doing), take the time to change all of these fluids out. For roughly $50, I was able to purchase new fluid for the front diff, rear, diff, and the transfer case. It really only takes a couple hours to change them all. And you might be surprised how dirty the fluid may be. My transfer case fluid was barely red anymore. It was long over due for a change.

 

do you have a write up or parts list of any kind for this? Would love to do it tomorrow, but not quite sure what i need to get or where to get it...

 

I think you may have gotten some moisture in it. It kind of looks like that milky stuff when you blow a headgasket.
Hard to tell from the pictures though. Thanks for posting pictures.

 

I ended up getting Valvoline 85-140 synthetic blend for $7/quart for the rear diff. I tried to find 75-140 as outlined in the owners manual, but couldn't find it.
For the front diff, I bought the 75-90 synthetic blend from walmart. It was roughly $5.50/quart which was a few bucks cheaper than autozone for the same weight of oil. I figured since I don't use 4WD that often, walmart synthetic oil would be just fine.
For the transfer case, I bought castrol mercon atf at autzone for roughly $4.50/quart. I already had a couple tubes of RTV so I didn't factor that into the overall cost.

My choices of stores was limited to Autozone, O'Reilly's, and Walmart. For me, autzone had the biggest variety of choices and comparable prices. The O'Reilly's by my house had basically one choice for each weight of oil. Not sure if this is typical of all O'Reilly's. As far as a write up, check guzzles website. He has step by step instructions with pictures and includes all of the torque settings. That's the write-ups I looked over before I did the work myself. It's really a straight forward job. No surprises or tricks. As far as capacities of each fluid check your owners manual or they can tell you at any autoparts store. I was confused on the front diff and they were more than happy to look it up at the counter.

That thought had crossed my mind. I think you confirmed it. I have no idea when the last time it was done so I figured I should change it regardless.

 

Boy, that don't look right. Even under very extreme circumstances, gear oil shouldn't foam like that at all.

 

where is the smilie face on the diff cover? get back under there and paint one on.

 

Looks good Clay. I talked to Joey at Termy tonight.. I should have an idea when your modded 17* gets in..

 

X2, big difference between an oily foam and a dish detergent looking foam. I wonder if anybody like the PO spiked the rear with something to keep it quiet, like the oatmeal trick or something simular.

 

Welcome to guzzle's Ford PSD Maintenance Web Page

 

Coming from an offroading background, I've seen a few diffs that had water inside and it doesn't look like that. It looks more like a chocolate shake. How warm do you think the diff was after your warm up run? I wonder if it was still really cold and that's how the cold oil reacted to being churned up. If you look at the standing oil on the spider gear teeth in pic four, the fluid looks new. The flash is making it a bright neon color but the fluid looks good. I think you're ok.

 

Haha well it's a little too cold for me to spend that much time on the cover. Maybe when it gets warmer

Sweet! thanks bud!

Not sure. I should have an idea when I get the rear cover off today.

I drove it with the 4wd engaged for about 10-15 mins. When I got under and put my hand on the cover, it was barely warm. I probably should have drove it longer but I was getting impatient haha. The fluid itself was still somewhat cool to the touch but nowhere near the temperature it was outside. I didn't notice any metal shavings in the oil or any pieces of anything in the bottom of the diff when I drained it.

 

Put it in a clear container and see if it seperates. That will tell you for sure.

 

That's a good suggestion. I wish I would of thought of that before I put it in the mystery oil bucket

 

UPDATE:

I got to the rear diff today. The pictures/info can be found in this thread:

https://www.ford-trucks.com/forums/1...e-w-pics.html?